This invention relates to a control center having internal control units that hang from a unit shelf within the control center.
Control centers are generally made up of a number of separate control center sections that are placed side by side. Each central center section houses a number of control units vertically stacked one on top of the other. Electrical power is supplied to the control center via horizontal bus bars located in the back of the control center. Power is distributed through the horizontal bus bars and the vertical bus bars that run the length of each section to the individual control units. Each control unit must be properly positioned on the a respective shelf, since the circuit breaker or switch that is mounted within each control unit must be electrically connected with the appropriate vertical bus bars. The tolerance for this connection is low since the fit between the circuit breaker or switch and the vertical bus bar must be tight to accommodate the power flow through the joint. In the prior art, a control unit was placed in the proper location by positioning the screw holes of the control unit with the screw holes of a respective shelf. This method is relatively time consuming and hence costly.
The prior art shelf also had separate procedures for securing the shelf and the door to the frame of the control center section, each with its own individual connectors. Since a control center section often has a large number of control units, each with associated doors and shelves, any reduction in the number of operations or components required for plant assembly results in a large savings in production costs. Users likewise save time and expense in making any desired modifications to the control units.
It is an object of the present invention to provide a control center having a quick installation procedure for the control unit assembly.
It is a further object of this invention to provide accurate alignment of the circuit breaker or switch with the vertical bus bar within a control center.
Another object is to provide a control unit with easier and more economical assembly of the shelves, doors, and other components thereof.
Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments.